#include <cstdio>

int main( )
{
    int n, a[ 1000 ], i, j;
    while ( scanf("%d", &n) != EOF )
    {
        for ( i = 0; i < n; i++ )
            scanf("%d", &a[ i ]);
        for ( i = 'A'; i <= 'Z'; i++ )
        {
            for ( j = 0; j < n; j++ )
                if ( ( i ^ a[ j ] ) > 'Z' || ( i ^ a[ j ] ) < 'A' )
                    break;
            if ( j == n )
                break;
        }
        for ( j = 0; j < n; j++ )
            printf("%c", i ^ a[ j ]);
        printf("\n");
    }
    return 0;
}
